From a quick look through remoteStorage, it looks to me like it's is focused on storage (and so appropriately named!), while Edsu is more explicitly a foundation for applications.

One place this shows up is that Edsu has a permissions model where other people can read and interact with what you've stored (within very tightly defined parameters), which is the basis for writing multi-user apps like, say, a distributed Reddit or Slack.

They both have the same model regarding the ownership of data though. The biggest difference there is that Edsu uses a Merkle tree as the storage, like IPFS and git, which has a lot of consequences in terms of how it gets used.

This is the first I've heard of Edsu as well, but when I checked out NoteToMe, the first thing I noted is that you should create an account first. It's probably not inherent to the protocol, but the nice thing about RemoteStorage is that the default library already starts with localStorage first, and allows you to only sync that data to an account later.

Compare https://litewrite.net, a RemoteStorage app presumably similar to NoteToMe. You can start writing immediately, and sign in with a RemoteStorage account only if you want that data to be available elsewhere as well.